The very first part of the road is paved (booo!!!!!) because there was originally going to be logging activity out here and the loggers paved it in anticipation of that. The logging fell through, and the paved road peters out shortly after the Nez Perce Pass.
Magruder has some distinction among off road drivers. It's not super technical - again, like Lolo, you could get a car up it if it wasn't your car - but it's fun regardless of the lack of skill required to do it.
It's also long, and tiring. Like Lolo, it's a day trip, especially with stops.
Here's the other thing about Magruder: information about it varies a great deal, and some of it is just stupidly wrong. For example, I read an online article describing it, and it made it sound like some apocalyptic shit, stating that you couldn't get through without 2 spare tires, a winch, a come along, a sat phone, and a note from the President and the Surgeon General. That same article claimed the "highlight" of the road is the Nez Perce Pass (pictured above) and that it is the highest point on the road at 6,500 feet. That article also claimed that there were a few roads leading off Magruder that were fun and interesting and it very casually indicated that they "required 4WD". The directions given to the eastern 'starting point' of the route are not even correct - they have the wrong road names and numbers listed.
To clarify, the Nez Perce Pass sucks my dick, and is basically a sign in the ground. There's nothing to see there, and all the awesome vistas are well west of it. The highest point on the road is well over 8,200 feet, as verified with my GPS. The roads "requiring 4WD" - which sounds like something a Subaru could do -actually require a very high clearance rig with larger tires and lockers, and are not for casual AWD / 4WD operators; while the road itself requires nothing more than a unicycle with a knobby on it.
I question whether some of the people who have authored articles about this road have even driven it. Here's the article I read, let's mock him together:
Also, the national forest maps available online are awful at depicting the route. I tried to buy an actual map at the Lolo Pass Ranger Station, but they were sold out.